Just like with drinking water filters there are a lot of companies and “health experts” that spread unscientific or even false information for their own benefits.Therefore we’ve tried to capture the most common ones here.
We want to make clear a few facts about water you might want to know about
1. Facts about water: Shower filters remove all chlorine
Good filters remove 90% or more but there are filters that don’t remove chlorine at all. The ones that claim 99% removal are most likely made up results. Filters that are certified by the NSF #177 Standard (the US water filter standard) — only indicates that a filter will remove 50% of free chlorine in the water.
Make sure that the the manufacturers provide independent test results for their filters before buying.
2. KDF shower filters are the most effective at removing chlorine
Another fact about water is that KDF removes “free chlorine” (chlorine that has not combined with other constituents in water) under heavy pressure with hot water.
Carbon filters are virtually useless in showers, because they do not work when the water is warm, high pressure and they also get clogged fairly quickly.
The claim that Vitamin C filters remove chlorine is more complicated. We’ve tried to find independent research that shows the effectiveness without success. Vitamin C does work in the bathtub though as there is sufficinet time for the water and Vitamin C to mix.
In an interview by Bloomberg Neal Langerman at the American Chemical Society Division of Chemical Health and Safety. “From a chemistry standpoint, vitamin C does react with chlorine and consume it. The concept has even been proven by the U.S. Department of Agriculture. But the filters are all hype. First off, chlorine and chloramines do not cross the skin barrier, nor does vitamin C. … [Also] I don’t think the reaction would be complete—the neutralization, if you will—by the time the water hits your head or flows down the drain.”
The conclusion from our research is that Vitamin C is most like insufficient on it’s own but combined with KDF it could be.
3. The skins absorps chlorine when showering
Some blogs and websites claim that a 10-minute shower causes your body to absorb the equivalence of 8 to glasses of chlorinated drinking water.
The health risks caused by chlorine absorption are explained as follows in a paper by The Department of Community Health:
“The skin does not absorb chlorine well, but small amounts can pass through the skin when people are exposed to chlorine gas, bleach, or come into contact with water or soil containing high levels of chlorine. Although small amounts of chlorine can pass through the skin, it is eliminated from the body rapidly. Chlorine may irritate or burn the skin, especially moist areas.”
4. Chloroform (one of the THMs) which may be cancer-causing can form when showering in chlorinated hot water
Following with the facts about water we know, there is plenty of evidence and research although the bigger studies are still ongoing to assess the long term health effects.
Science News reported that researchers found increases in chloroform in study participants’ lungs of about 2.7ppb after a 10-minute shower. Combined with warm water opening pores, skin absorption and lung inhalation during a 10-minute shower showed to be greater than the amount that would be ingested by drinking 8 glasses of the same water.
5. Shower filters can remove chloramines
Chloramines are used instead of chlorine by some public water suppliers. Many of the shower filter brands and especially vitamin C ones claim that they can also remove chloramines.
There are no conventional shower filters that will remove more than a small amount of chloramines from your shower water.
San Francisco Public Utilities Commission states on their website that only Vitamin C can be used to remove chlormaines from municipal water but the test was carried out using 1000 mg of Vitamin C in bath water,
On the other hand there is plenty of evidence that it will not be as effective for a shower filter. Screw on type of shower filters that claim to eliminate choramines are unlikely to work. While they may reduce chloramines slightly, it is highly dubious that they actually eliminate chloramines because the flow of water through a shower filter is too high to result in contact of the water with the filtering compound for a long enough duration of time.
Be sure to check out the claims of these chloramine filter manufacturers. Ask for independent research that proves the effectiveness of their shower filters. You probably won’t find it. We haven’t been able to find any. Facts about water in your shower are very important to be known.
The only way to effectively remove chloramines in your shower is to have a whole house filtration system.
6. Shower filters soften the water?
A shower filter will not soften water in the way a traditional softener does, but it will remove chlorine and other chemical contaminants, making the water much less harsh and leaving your skin and hair feeling significantly softer.
7. Shower filters reduce water pressure?
Most shower filters process water at 10 Liters (2.5 gallons) per minute, which is the same flow regulation as most standard shower heads.
However, it’s not a bad idea to combine your filter with a water saving shower head to save water consumption and money. You can find a list and review of shower heads here.
8. Shower filters last 12 months or more
Based on two 10-minue showers per day most KDF filters last 3-6 months. Unfortunately it’s difficult to notice the difference between fully effective and partially so better be safe than sorry and change as frequent as the manufacturer recommends.
9. Vitamins C infused shower filters are better for the skin
According to Patricia Farris, a doctor that specialises in dermitology Vitamin C has lots of benefits for the skin. It can be absorbed through the skin if it is formulated properly. Vitamin C can soften lines and wrinkles by boosting collagen production, lighten hyperpigmentation, and protect the skin from UV damage.”
But will it work with a shower filter?
“Most likely not. While a vitamin C-infused shower sounds good in theory, it will probably provide very little skin benefit,” says Farris. “Vitamin C must be formulated and packaged in a very careful way in order to stabilize it and prevent it from becoming oxidized [which makes it ineffective]. If it’s just sprayed out of the shower, the majority of it will be inactivated rather quickly as it is exposed to air.”
There is no scientific evidence that Vitamin C showers benefit the skin.
10. Showering and bathing with chlorinated is bad for pregnant women and childrent
For women who are pregnant, chlorinated water may not only put the mother’s health at risk, but the unborn child as well.
A study conducted by a team in England determined that women who drank or took showers in unfiltered water laced with chlorine and chloramine contamination resulted in various complications with the pregnancy, including spontaneous abortions, stillbirth, low birth weight, premature delivery, and a spectrum of birth defects ranging from nerve damage to weak hearts.
For children, a hot bath or shower with unfiltered municipal water could have dangerous effects on their development. In Belgium, a study was done to find out if there was any correlation between school children who spent time breathing the air in an indoor swimming pool and an increase in lung permeation and the development of asthma.
Children who played frequently at the pool had an increased risk of developing juvenile asthma, and in some cases the symptoms were severe.
They also had more damaged epithelial tissue, which is the tissue that makes up the outer layer of skin and lines the insides of the lungs. This study confirms just how harmful chlorine vapors can be for a child’s respiratory system, not just in community pools, but at home in showers and baths, too.
Real conclusions can not be drawn from the limited studies, especially not since no studies specifically on the effects of showering in relation to pregnancy have been done. Considering the other health hazards it may be wise to be better safe than sorry though.